1. Field of the Invention
This disclosure is directed to intravascular surgery, more particularly, to a sheath or catheter having a deflectable distal end portion that is controlled by a unidirectional steering handle.
2. Description of Related Art
Guiding catheters (“sheaths”) are commonly used to introduce balloon catheters and stents into the vascular system (e.g., for percutaneous transvascular coronary angioplasty), to introduce cardiac pacing leads into the coronary sinus (e.g., for left ventricular pacing and cardiac resynchronization procedures), to introduce drugs into the human body, and/or to introduce radiofrequency ablation catheters into the left atrium (e.g., for treatment of atrial fibrillation) into the renal artery for renal denervation procedures.
Guiding sheaths typically come in French sizes ranging from 4F all the way to 12F, and in some cases even 18F. Sheaths generally include an inner lumen that extends from the proximal portion of the device to the distal tip section of the device. The inner lumen often has a polytetrafluoroethylene (PTFE) liner to make the insertion of a device therethrough as easy and as smooth as possible.
Intravascular sheaths with a deflectable distal portions have the advantage of being introduced into a blood vessel in a straight condition, and thereafter the device can be remotely steered into a desired location by deflection the distal tip of the sheath, even though torturous and tight vessels. A common problem associated with traditional deflectable catheter sheaths is that, once they have been deflected, they do not readily return to a completely straight position for removal from the target location at the end of a procedure. This can inhibits the sheath from being easily retracted or withdrawn through the blood vessel or advanced into other desired locations within the vasculature of the patient.
Additionally, a wire inside the steering assembly that is connected to the distal end of the sheath can become twisted or create an undesirable force on the proximal end of the sheath where the wire enters the sheath when the device is operated between deflected and non-deflected states. Such undesirable forces and degrade the wire and/or the sheath, potentially compromising the functionality thereof.
While traditional guiding sheaths have been satisfactory for their intended purpose, a need exists for improved guiding catheters and steering assemblies. This disclosure provides solutions for these needs.